## Reverse engineering wireless wall outlets

July 19, 2014
Introduction

I am improving the domotics framework that I described in a previous article://www.embeddedrelated.com/showarticle/605.php

I want to support wireless wall outlets, allowing me to switch devices power from a remote location over HTTP.

To do so, I could design my own wireless wall outlets and use a hardware similar to the previous one, based on the NRF905 chipset. The problem is that such a product would not be certified, and that would be an issue regarding the home insurance,...

## A wireless door monitor based on the BANO framework

Introduction

I have been thinking for a while about a system to monitor the states of my flat and my garage doors from a remote place. Functionnaly, I wanted to monitor the state of my doors from a remote place. A typical situation is when I leave for holidays, but it can also be useful from the work office. To do so, I would centralize the information on a server connected on the Internet that I could query using a web browser. The server itself would be located in the appartement, where...

## Using a RTLSDR dongle to validate NRF905 configuration

I am currently working on a system to monitor the garage door status from my flat. Both places are 7 floors apart, and I need to send the data wirelessly. I chose to operate on the 433MHz carrier, and I ordered 2 PTR8000 modules: http://www.electrodragon.com/w/NRF905_Transceiver_433MHz-Wireless_ModuleThe PTR8000 is based on the dual band sub 1GHz NRF905 chipset from NORDICSEMI: http://www.nordicsemi.com/eng/Products/Sub-1-GHz-RF/nRF905I...

## How to Arduino - a video toolbox

November 15, 20131 comment

I've begun producing a new series of video tutorials for the hobbyist new to the Arduino or microcontrollers in general.  My videos are very pragmatic - I prefer to answer the question "what is the quickest, simplest and most affordable way to accomplish this?".  The videos are meant to be a quick source of "how to" knowledge for the hobbyist that is using an LCD display, ultrasonic sensor or accelerometer for the first time, for example.  I hope you enjoy this series of...

## Introduction to Microcontrollers - Driving WS2812 RGB LEDs

This tutorial chapter is a bit of a detour, but I think an interesting and useful one.  It introduces a bit of assembly language programming, and demonstrates bit-banging a tight serial data protocol.  And it deals with RGB LEDs, which are just very fun in their own right, especially these new parts.  So I thought I'd post this to give readers time for some holiday lighting experimenting.

Back To The Future

Remember how we started this...

## Introduction to Microcontrollers - Button Matrix & Auto Repeating

November 12, 2013

Too Many Buttons, Not Enough Inputs

Assigning one GPIO input to each button can use up a lot of GPIO pins.  Numeric input requires at least 10 buttons, plus however many additional control or function buttons.  This can quickly get expensive, GPIO pin-wise, and also connector-wise if the keypad is off the uC PCB as it often would be.  A very common response to this expense is to wire buttons (keys, etc) in a matrix.  By connecting our buttons in an...

## Energia - program a TI MSP430 using Arduino sketches

November 5, 20131 comment

I started tinkering with microcontroller a couple of years ago with an Arduino Uno.  I had a little experience with C, so programming in the Arduino environment has been relatively easy and straightforward for me.  My code is not necessarily elegant or efficient, but I can usually figure out how to make an Arduino do what I want it to do eventually.  A lot of credit to the Arduino userbase, as it is very easy to figure most things out with a quick Google...

## Embedded Systems - free EdX course by UT-Austin!

October 29, 20131 comment

I was very excited to see that there will be an Embedded Systems class available for free at https://www.edx.org/course/utaustin/ut-6-01x/embedded-systems-shape-world/1172

It's free to sign up and take the online class at the EdX website.

More exciting is that the class is based on a TI Launchpad Tiva microcontroller development board.  The Tiva Launchpad features an 80-MHz ARM Cortex M-4 MCU with 256 KB of flash storage, 32 KB of RAM and 43 general purpose I/O pins.

## Introduction to Microcontrollers - Buttons and Bouncing

What Is A Button?

To your hardware, that is.  As discussed in Introduction to Microcontrollers - More On GPIO, a button (or key, or switch, or any form of mechanical contact) is generally hooked up to a microcontroller so as to generate a certain logic level when pushed or closed or "active," and the opposite logic level when unpushed or open or "inactive."  The active logic level can be either '0' or '1', but for reasons both historical and electrical, an...

## Arduino robotics #4 - HC-SR04 ultrasonic sensor

October 20, 20131 comment
Arduino Robotics

Arduino robotics is a series of article chronicling my first autonomous robot build, Clusterbot.  This build is meant to be affordable, relatively easy and instructive.  The total cost of the build is around $50. 1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4. ## How to Arduino - a video toolbox November 15, 20131 comment I've begun producing a new series of video tutorials for the hobbyist new to the Arduino or microcontrollers in general. My videos are very pragmatic - I prefer to answer the question "what is the quickest, simplest and most affordable way to accomplish this?". The videos are meant to be a quick source of "how to" knowledge for the hobbyist that is using an LCD display, ultrasonic sensor or accelerometer for the first time, for example. I hope you enjoy this series of... ## Introduction to Microcontrollers - Adding Some Real-World Hardware October 8, 20132 comments When 2 LEDs Just Don't Cut It Anymore So far, we've done everything in this series using two LEDs and one button. I'm guessing that the thrill of blinking an LED has worn off by now, hard as that is to imagine. What's more, we've just about reached the limits of what we can learn with such limited I/O. We have come to the point where we need to add some hardware to our setup to continue with additional concepts and microcontroller... ## Cortex-M Exception Handling (Part 2) February 1, 20169 comments The first part of this article described the conditions for an exception request to be accepted by a Cortex-M processor, mainly concerning the relationship of its priority with respect to the current execution priority. This part will describe instead what happens after an exception request is accepted and becomes active. PROCESSOR OPERATION AND PRIVILEGE MODE Before discussing in detail the sequence of actions that occurs within the processor after an exception request... ## Energia - program a TI MSP430 using Arduino sketches November 5, 20131 comment TI MSP430 Launchpad I started tinkering with microcontroller a couple of years ago with an Arduino Uno. I had a little experience with C, so programming in the Arduino environment has been relatively easy and straightforward for me. My code is not necessarily elegant or efficient, but I can usually figure out how to make an Arduino do what I want it to do eventually. A lot of credit to the Arduino userbase, as it is very easy to figure most things out with a quick Google... ## Introduction to Microcontrollers - More Timers and Displays October 15, 20133 comments Building Your World Around Timers By now you have seen four different ways to use timers in your programs. Next we will look at some ways to produce the effect of multiple parallel streams of work in your program with the help of timers. This effect is only an appearance, not a reality, since a single microcontroller (one core) can only run a single thread of code. However, since microcontrollers are so fast in relation to a great many of the tasks to... ## A wireless door monitor based on the BANO framework June 10, 20145 comments Introduction I have been thinking for a while about a system to monitor the states of my flat and my garage doors from a remote place. Functionnaly, I wanted to monitor the state of my doors from a remote place. A typical situation is when I leave for holidays, but it can also be useful from the work office. To do so, I would centralize the information on a server connected on the Internet that I could query using a web browser. The server itself would be located in the appartement, where... ## Reverse engineering wireless wall outlets July 19, 2014 Introduction I am improving the domotics framework that I described in a previous article://www.embeddedrelated.com/showarticle/605.php I want to support wireless wall outlets, allowing me to switch devices power from a remote location over HTTP. To do so, I could design my own wireless wall outlets and use a hardware similar to the previous one, based on the NRF905 chipset. The problem is that such a product would not be certified, and that would be an issue regarding the home insurance,... ## Arduino robotics #2 - chassis, locomotion and power October 16, 2013 Arduino Robotics Beginner robotics is a series of article chronicling my first autonomous robot build, Clusterbot. This build is meant to be affordable, relatively easy and instructive. The total cost of the build is around$50.

1. Arduino robotics - motor control2. Arduino robotics - chassis, locomotion and power3. Arduino robotics - wiring, coding and a test run4.

## Metal detection: beat frequency oscillator

January 30, 20161 comment
Plan Introduction Theory Electronics Software Tests ReferencesNext part: building the detector 1. Introduction

This article discusses the implementation of a beat frequency oscillator (BFO) stage for metal detector. While they are mentioned here and there, the article does not detail other important electronic stages such as the power supply, and user interface, the coil or the detector frame. I may write other articles on these topics, and other detection methods.Before...